Device for selecting metal pieces



Sebi 7 1948. E. R. MANN E; A1. 2,448,814

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Patented Sept. 7. 1948 2,448,814 DEVICE FOR SELECTING METAL PIECES Estle Ray Mann, Upper Montclair, and Thomas Toliver Goldsmith, Jr., Cedar Grove Township.

Essex County, N. J Mont Laboratories, ration oi' Delaware anignors to Allen B. Du Inc.. Passaic.' N. J., a corpo- Applioatlon July 12. 194i, Seriai No. 544,608

(i. 20th-8l) Claims.

This invention relates to a device for selecting metal pieces, or separating such pieces from others which may lookllke them and are of the same shape and size.

It is known that when metal from metal stoci: the articles often diier from each other because oi differences in the metal stool: due to composition or heat treatment or other causes.

Ey the present invention such articles or metal pieces can be rapidly examined by means of a device that is simple in operation and rapid and accurate in results. The device does not require a high degree oi skill or prolonged training on the part of the operator. The unsatisfactory pieces can be separated by reason of signals they produce with the device or they can be separated from the satisfactory pieces automatically.

1n carrying out the invention signals are obtained by passing the articles in succession which is a portion of a device which is already known but which is not a part of the present invention, but which produces different signals inaccordance with the core losses such as hysteresis losses, eddy current losses. etc., that occur when the metal articles are passed through a the tank circuit of a high frequency oscillator. Signals from such a device are applied to the present device. This signal-producing device is indicated diagrammatically in Fig. 2 of the drawings and will be briey described later.

The present invention may be understood from the description in connection with the accompanying drawings, in which:

Fig. lo ls a diagram showing a portion of the device; l

Fig. 1b is a diagram showing another portion thereof; and l Fig. 2 is partly in section and partly diagrammatic showing how the pieces may be automatiarticles are made In the drawings, the indicated values of resistances and capacitances are illustrative.

Reference characters I,l 2 and 3 indicate vacnum tubes the control grids of which are coupled to the input terminal 4 by capacitor 5 and lead 5'. Resistors 6, 'l and Bare provided between the cathodes of tubes i, 2 and 3 and ground. Grid bias resistors 9, i0 and il of the tubes l. 2 and 3 are connected to intermediate points on the resistors 6, 'i and B, respectively.L f

The cathodes of tubes I, 2 and 3 are coupled by primaries oi transformers i6, i8 and i'l,leads it. it and i4. and capacitors 2i, 22 and 23, re-

coil that is a portion of liti spectively, to the grids of the blocking oscillator tubes 24, 3B and 2B. The plates of these tubes are connected through secondaries 21', 28' and 29' oi' the transformers i8, i9 and 20. to a source of direct current which is also connected to the plates of tubes i, 2 and 3.

Cathode biasing resistors 2l, 28 and 29 are connected in the cathode circuits of the tubes 24,

at and 2t?. By-pass condensers 80, 3i and 32 are provided for the resistors 2l, 28 and 29. Grid biasing resistors 33, 84 and 35 are provided for the tubes 26, 2li and 2B and are connected by sliding` contactors to the resistors 38. 31 and 38 that are in parallel with portions oi the resistors 2l. 2d and 29, respectively. Resistors 39, 40 and All are provided between the source oi current for the plates of tubes 24, 25 and 2B and the cathods of these tubes.

Secondaries 42, 43 and 44 of the transformers i8. i9 and 26 are connected by leads 45, 48 and 41 and capacitors 48, 49 and 50 (Fig. 1b), to the control grids of tubes 5|, 52 and U3. These tubes are provided with -grid leak resistors 54, 55 and 5B and are adjustable by means of the sliding contactors 84', 5B', 58'.

cons so, si and sz of relays sa, u and `sr are. located between a source S of direct current and.

the plates of tubes 5l, B2 and 53, respectively. The relay arms 88, 61 and 8l are provided with contactors 89, 'l0 and ii for their upper positions and with contactors l2. ll and 'i4 for their lower positions.

A source i5 of alternating current is connected ,through the fuse 'i8 to the relay arm 68 and 8i', 82 and 92' are provided. The arms 80, 9i.

through the switch 'l'l to the lead 18. Lead 80 connects the contactor 'I4 to the relay arm B'l. and lead 8i connects 'contacter arm B6.

Relay coils 44, 85 and 88 are provided for re lays 81, 88 and 8l, for which relay arms 80, 9i,

and 8i' are connected to lead 8i and the arms 92 and 82 are connected to the lead 80. Electric lamps 93. 84 and 95 are connected between lead 'l0 and relay arms 90. 8i and 42, respectively. When these arms Sil, 9| and 82 are in their closed positions, the lamps 83, 94 and ll are lighted.

Reference character |00. Fig. 2, indicates the inductance coil mentioned above through which the articles to be tested or examined are passed. and reference character IM indicates diagrammatically the already known device which produces high frequency signals of different ampli` tudes in accordance with the core losses, such as hysteresis losses, eddy current losses, etc.. which 13 to the relayv occur when the specimens are passed through the coil |00, these specimens being of the same shape, size and material. Reference characters 4 and 5 indicate the input terminal 4 and capacitor 5 shown on Fig 1a, and the block |02 represents the device described above in connection with Figs. la and 1b.

The hinge |04 in the side of the conduit |03 is for the door 92 that is operated by the coil 86, Fig. 1b, simultaneously with the arm 82 to swing the door92 to the dotted line position and the hinge ||l6` is for the door 8|' that is operated by the coil 85 simultaneously with the ar-m 8| to swing the door 8| to the dotted line position. Plates and |01 along the sides of the conduit |03 are for diverting the articles that are not standard to the sides so that they are separated from the standard ones which enter the container H0. I

The operation is as follows:

The sliding contact on the resistor 38 in the cathode circuit of tube 26 is adjusted so that the oscillator 26 will oscillate when a signal is applied at the input terminal 4 due to a test specimen being dropped through the coil |00, Fig. 2, that has a smaller core loss than the standard. Tubes 24 and 25 are kept from oscillating at this signal level by adjusting the contactors on resistors 36 and 31.

The oscillation of tube 26 applies a positive signal pulse from coil 44 through lead 41 to the control grid of tube 53. This causes ilow of grid current in tube 53 which charges condenser 50 and grid of tube 53 negatively, thus decreasing the current through coil 62 and permitting the relay arm 68 to contact with contactor 14 which closes the circuit from generator through fuse 16, contactor 14, lead 80, contactor 10, coil 66, and switch 11 back to generator 15. This causes the coil 86 to close the relay arm 92 to flash the lamp 95. The coil 86 also operates the gate 92 in the usual way which causes the specimen to be diverted to the outside along the plate |05, Fig. 2. The length of time the gate 92 remains open can be controlled by the position of contactor 56 on a portion of resistor 56.

The sliding contact on the resistor 31 in the current passes from source 16 through arm 68, contactor 14, lead 80, arm 61, contactor 13, lead 8|, arm 66, contactor 12, coil 85, and lead 18 to source 15. The current through coil 85 causes it to close the relay arm 8| and flash the lamp 94. The coil 85 also operates the gate 6I' which causes the specimen to be diverted to the outside along the plate |01, Fig. 2. The length of time the gate 8|' remains open is controlled by the position of contactor 54 on a portion of rcsistor 54. h

By the present invention means are provided whereby each object to be tested is caused to produce a relatively short impulse signal while passing through a coil. The circuit converts this short signal to an output control pulse by means of one or more blocking oscillators which in turn actuate time constant networks illustrated by condensers 48, 49 and 50 working respectively with resistors 54, 55 and 56. so that delayed action longer interval signals are produced. Thus the passage of an object through the coil |00 is caused to generate a controlling signal lasting suillciently long for a finite travel interval of the object through the coil |00l and on through thelsorting conduit |03 and gates |05 and |01. This memory mechanism is highly important for satisfactory sorting.

While most of the above description of the invention relates to the sorting of metal pieces that are capable of producing electrical signals characteristic of core losses, the invention is also suitable for or useful in selective sorting of varicathode circuit of tube 25 is adjusted to apoint where a standard specimen passed through the coil |00 will cause the oscillators 25 and 26 to oscillate because of the core losses without causing the oscillator 24 to oscillate. The grid of tube 52 is made negative as described above in connection with tube 53 so that the relay arm 61 contacts with contactor 13 and prevents current from passing through coil 86. Current passes from generator 15 through arm 68, since coil 62 is then also de-energized at the same time as coil 6I. This current'also passes through the lead 80, contactor 13, lead 8|, relay arm 66, contactor 69 and coil 84 back to generator 15. The flow of current through coil 84 closes contactor 90 and-flashes the light 93. The standard specimen, or one like it, therefore passes through the conduit |03 into the container |I0.

The sliding contact on resistor 36 in the cathode circuit of tube 24 is adjusted to a point where the oscillator will oscillate only 'when a specimen that has core losses greater than the standard piece is passed through the coil |00. Under such a condition the outputs from the .l coils 42, 43 and 44 of oscillators 24, 25 and 26 decrease the currents through coils 60, 6| and l 62 so that contact arms 66, 61 and 68 drop to contacts 1 2, 13 and 14, respectively. Therefore,

ous other types of objects, including non-metallic objects. It is only necessary that the several objects under test be capable of producing respective electrical signals which can be applied to the input terminal 4 of the device.

A particular advantage of this invention, applied to any types of objects, is the ability of the device to respond to a predetermined middle range of amplitudes and at the same time it is non-responsive to signals both above and below the predetermined mid-range of amplitude of the electrical signals that may be produced.

What is claimed is:

l. A device for separating metal pieces of the same shape and size but having different core losses when subjected to alternating magnetic fields, which comprises a series of blocking tube oscillators connected in parallel and so adjusted that a stronger pulse is reouired to cause each one in said series to oscillate than is required for the preceding one, relays connected to the outputs of said oscillators and adapted to be closed seriatim by said oscillators, and means controlled by said relays to sort said metal pieces in accordance with their having high, medium or low core losses when subjected to said ilelds.

2. The device of claim 1 in which there are three blocking tube oscillators in said series.

3. The device of claim l in which there'are time constant networks actuated by the outputs of said blocking tube oscillators.

4. The device of claim l in ywhich there-are time constant networks actuated by the outputs of said blocking tube oscillators and located between the outputs of saidv oscillators and said relays,

5. The device of claim 1 in which signalling means'are provided to show when said relays are closed. l

ESTLE RAY MANN. v THOMAS TOLIVER GOLDSMITH, JR.

(References on following page) 5 f REFERENCES CITED Tho following references are ot record in the ille of this patent:

UNITED STATES PATENTS 5 Number Name Date 673,519 Foster 1 May "I, 1901 1,593,993 Sprague July 27, 1926 1,771,700 Alexanderson July 29, 1930 m Number l Name Date Buyko Apr. 21, 1931 Francis Aug. l18, 1931 D emarest Jan. 8, 1935- Grtcken June 30, 1936 White Apr. 5, 1938 Cox Dec. 2, 1941 O'dquist'. Mar. 2, 1943 Leathers June 6, 1944- 

